1 files changed, 36 insertions, 6 deletions

diff --git a/arch/arm/xen/p2m.c b/arch/arm/xen/p2m.c
index e52950a43f2e..9da57a5b81c7 100644
--- a/arch/arm/xen/p2m.c
+++ b/arch/arm/xen/p2m.c
@@ -11,6 +11,7 @@
 
 #include <xen/xen.h>
 #include <xen/interface/memory.h>
+#include <xen/grant_table.h>
 #include <xen/page.h>
 #include <xen/swiotlb-xen.h>
 
@@ -62,11 +63,12 @@ out:
 
 unsigned long __pfn_to_mfn(unsigned long pfn)
 {
-	struct rb_node *n = phys_to_mach.rb_node;
+	struct rb_node *n;
 	struct xen_p2m_entry *entry;
 	unsigned long irqflags;
 
 	read_lock_irqsave(&p2m_lock, irqflags);
+	n = phys_to_mach.rb_node;
 	while (n) {
 		entry = rb_entry(n, struct xen_p2m_entry, rbnode_phys);
 		if (entry->pfn <= pfn &&
@@ -93,15 +95,43 @@ int set_foreign_p2m_mapping(struct gnttab_map_grant_ref *map_ops,
 	int i;
 
 	for (i = 0; i < count; i++) {
+		struct gnttab_unmap_grant_ref unmap;
+		int rc;
+
 		if (map_ops[i].status)
 			continue;
-		set_phys_to_machine(map_ops[i].host_addr >> XEN_PAGE_SHIFT,
-				    map_ops[i].dev_bus_addr >> XEN_PAGE_SHIFT);
+		if (likely(set_phys_to_machine(map_ops[i].host_addr >> XEN_PAGE_SHIFT,
+				    map_ops[i].dev_bus_addr >> XEN_PAGE_SHIFT)))
+			continue;
+
+		/*
+		 * Signal an error for this slot. This in turn requires
+		 * immediate unmapping.
+		 */
+		map_ops[i].status = GNTST_general_error;
+		unmap.host_addr = map_ops[i].host_addr;
+		unmap.handle = map_ops[i].handle;
+		map_ops[i].handle = INVALID_GRANT_HANDLE;
+		if (map_ops[i].flags & GNTMAP_device_map)
+			unmap.dev_bus_addr = map_ops[i].dev_bus_addr;
+		else
+			unmap.dev_bus_addr = 0;
+
+		/*
+		 * Pre-populate the status field, to be recognizable in
+		 * the log message below.
+		 */
+		unmap.status = 1;
+
+		rc = HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref,
+					       &unmap, 1);
+		if (rc || unmap.status != GNTST_okay)
+			pr_err_once("gnttab unmap failed: rc=%d st=%d\n",
+				    rc, unmap.status);
 	}
 
 	return 0;
 }
-EXPORT_SYMBOL_GPL(set_foreign_p2m_mapping);
 
 int clear_foreign_p2m_mapping(struct gnttab_unmap_grant_ref *unmap_ops,
 			      struct gnttab_unmap_grant_ref *kunmap_ops,
@@ -116,7 +146,6 @@ int clear_foreign_p2m_mapping(struct gnttab_unmap_grant_ref *unmap_ops,
 
 	return 0;
 }
-EXPORT_SYMBOL_GPL(clear_foreign_p2m_mapping);
 
 bool __set_phys_to_machine_multi(unsigned long pfn,
 		unsigned long mfn, unsigned long nr_pages)
@@ -124,10 +153,11 @@ bool __set_phys_to_machine_multi(unsigned long pfn,
 	int rc;
 	unsigned long irqflags;
 	struct xen_p2m_entry *p2m_entry;
-	struct rb_node *n = phys_to_mach.rb_node;
+	struct rb_node *n;
 
 	if (mfn == INVALID_P2M_ENTRY) {
 		write_lock_irqsave(&p2m_lock, irqflags);
+		n = phys_to_mach.rb_node;
 		while (n) {
 			p2m_entry = rb_entry(n, struct xen_p2m_entry, rbnode_phys);
 			if (p2m_entry->pfn <= pfn &&